Titanium Dioxide Particle Type and Concentration Influence the Inflammatory Response in Caco-2 Cells.

Saeko Tada-Oikawa,Kiyora Izuoka,Gaku Ichihara,Masahiko Murakami,Hitomi Fukatsu,Yuka Suzuki,Natsuki Tanaka,Yuka Shimanuki,Eri Watanabe,Yoshiji Yamada,Wenting Wu,Jie Chang,Sahoko Ichihara

doi:10.3390/ijms17040576

Saeko Tada-Oikawa, Kiyora Izuoka + Show 11 more

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https://doi.org/10.3390/ijms17040576

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Abstract

Titanium dioxide (TiO2) nanoparticles are widely used in cosmetics, sunscreens, biomedicine, and food products. When used as a food additive, TiO2 nanoparticles are used in significant amounts as white food-coloring agents. However, the effects of TiO2 nanoparticles on the gastrointestinal tract remain unclear. The present study was designed to determine the effects of five TiO2 particles of different crystal structures and sizes in human epithelial colorectal adenocarcinoma (Caco-2) cells and THP-1 monocyte-derived macrophages. Twenty-four-hour exposure to anatase (primary particle size: 50 and 100 nm) and rutile (50 nm) TiO2 particles reduced cellular viability in a dose-dependent manner in THP-1 macrophages, but in not Caco-2 cells. However, 72-h exposure of Caco-2 cells to anatase (50 nm) TiO2 particles reduced cellular viability in a dose-dependent manner. The highest dose (50 µg/mL) of anatase (100 nm), rutile (50 nm), and P25 TiO2 particles also reduced cellular viability in Caco-2 cells. The production of reactive oxygen species tended to increase in both types of cells, irrespective of the type of TiO2 particle. Exposure of THP-1 macrophages to 50 µg/mL of anatase (50 nm) TiO2 particles increased interleukin (IL)-1β expression level, and exposure of Caco-2 cells to 50 µg/mL of anatase (50 nm) TiO2 particles also increased IL-8 expression. The results indicated that anatase TiO2 nanoparticles induced inflammatory responses compared with other TiO2 particles. Further studies are required to determine the in vivo relevance of these findings to avoid the hazards of ingested particles.

Highlights

Engineered nanoparticles (NPs), defined as particles with diameters of less than 100 nm, exhibit new physicochemical features at the nanoscale, such as large surface area, altered electronic properties, reactivity, and surface derivatization [1,2]
The intensity-weighted hydrodynamic average diameter (z-average) of dispersed NPs was measured by the dynamic light scattering (DLS) technology, as described previously [14,15]
Since TiO2 nanoparticles are widely used in various fields, including the food industry, understanding their behavior and effects on the intestine is essential for risk assessment

Summary

Introduction

Engineered nanoparticles (NPs), defined as particles with diameters of less than 100 nm, exhibit new physicochemical features at the nanoscale, such as large surface area, altered electronic properties, reactivity, and surface derivatization [1,2]. TiO2 NPs are typically synthesized in three different crystalline structures; anatase, rutile, or brookite [6], and the first two types are mainly used as industrial materials. Because of their low degree of toxicity and physicochemical properties, TiO2 NPs are widely used in a broad range of products, such as toothpaste, sunscreen, cosmetics, pharmaceuticals, and nanomedical reagents [7,8,9]. The use of engineered NPs in the food industry has been growing rapidly, based on added benefits, such as improved taste and texture, prolonged shelf life, and enhanced nutritional qualities [10]

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